Browsing by Author "Lin, Wei-Chieh"

Now showing 1 - 5 of 5

Efficient inverted quasi-bilayer organic solar cells fabricated by using non-halogenated solvent processes
(2014-09-07)
Chang, Jung-Hao
;
Wang, Hsiao-Fang
;
Lin, Wei-Chieh
;
Chiang, Kai-Ming
;
Chen, Kuan-Chen
Here we demonstrate the fabrication of novel, "quasi-bilayer" inverted organic photovoltaic devices using halogen-free solvents. The inferior solubility of pristine fullerene in non-halogenated solvents was used to control the interpenetration of upper polymeric donor layers with bottom fullerene layers. Notably, island-like nano-morphologies were revealed by AFM, SEM, TEM, cross-sectional TEM images and PL quenching measurement. Correlation between device performance, thin-film nano-morphology and ac impedance was observed. High efficiencies of 6.55% and 7.15% were observed for PBDTTT-C-T and PTB7 cells, respectively. These results demonstrate that this novel process not only offers an effective new method to control the morphology of solar active layers but, more importantly, could also be applied to a wide range of current material systems to produce efficient devices that comply with the non-toxic halogen-free requirement.
Efficient inverted quasi-bilayer organic solar cells fabricated by using non-halogenated solvent processes
(2014-09-07)
Chang, Jung-Hao
;
Wang, Hsiao-Fang
;
Lin, Wei-Chieh
;
Chiang, Kai-Ming
;
Chen, Kuan-Chen
Here we demonstrate the fabrication of novel, "quasi-bilayer" inverted organic photovoltaic devices using halogen-free solvents. The inferior solubility of pristine fullerene in non-halogenated solvents was used to control the interpenetration of upper polymeric donor layers with bottom fullerene layers. Notably, island-like nano-morphologies were revealed by AFM, SEM, TEM, cross-sectional TEM images and PL quenching measurement. Correlation between device performance, thin-film nano-morphology and ac impedance was observed. High efficiencies of 6.55% and 7.15% were observed for PBDTTT-C-T and PTB7 cells, respectively. These results demonstrate that this novel process not only offers an effective new method to control the morphology of solar active layers but, more importantly, could also be applied to a wide range of current material systems to produce efficient devices that comply with the non-toxic halogen-free requirement.
Electrochemical photocatalytic degradation of dye solution with a TiO2-coated stainless steel electrode prepared by electrophoretic deposition
(2013-08-01)
Lin, Wei-Chieh
;
Chen, Chien-Hung
;
Tang, Han-Yu
;
Hsiao, Yu-Cheng
;
Pan, Jill Ruhsing
This study demonstrates a new model for the treatment of azo dye wastewater by means of a heterogeneous photocatalytic degradation coupled with the homogeneous electrochemical Fenton reaction, and is called electrochemical photocatalytic (ECPC) degradation. Titanium dioxide-coated stainless steel (P25-TiO2/SS) mesh was employed as a photo-anode, covered with a uniform layer of P-25-TiO2 using electrophoretic deposition (EPD) in a 2-propanol suspension with 10(-4) M Zn(NO3)(2), at a deposition time of 1 min. After annealing in air at 350 degrees C for 1 h, a crack-free, porous P25-TiO2 layer of ca. 2.14 mu m was obtained. Potential bias was used to enhance the photocatalytic degradation of P25-TiO2/SS towards the target pollutant, azo dye orange G, in an undivided cell under ultraviolet light irradiation. Heterogeneous photocatalytic degradation and a homogeneous electro-Fenton reaction occurred in the system simultaneously when H2O2 and Fe2+ were electrochemically generated on the graphite cathode and photo-anode, respectively, under a suitable potential bias, enhancing the de-colorization and removal of total organic carbon. (C) 2013 Elsevier B.V. All rights reserved.
Electrochemical Photocatalytic Degradation of Orange G Using TiO2 Films Prepared by Cathodic Deposition
(2014-01-01)
Wu, Tsai-Fang
;
Lin, Wei-Chieh
;
Hsiao, Yu-Cheng
;
Su, Chih-Hao
;
Hu, Chi-Chang
Herein, we report that organic dyes with poor adsorption on photocatalysts (e. g., OG (orange G) on TiO2) can only be significantly degraded via the indirect oxidation process by the electrochemical photocatalytic (EPC) or photo-electro-Fenton (PEF) mechanisms because of their enhanced electron-hole separation for generating H2O2. The TiO2/Ti photo-anodes were prepared by cathodic deposition from a bath containing TiCl3, HCl, H2O2, and NaNO3 under a two-electrode mode for EPC dye degradation. Effects of the deposition cell voltage, deposition time, and annealing temperature on the photocatalytic activity of TiO2 films, evaluated by the photocurrent density, are systematically investigated. The surface morphologies and crystalline structure of various TiO2 films were studied using scanning electron microscopic (SEM) and X-ray diffraction (XRD) analyses. The EPC characteristics of TiO2/Ti photo-anodes combined with a graphite cathode toward the OG degradation have also been evaluated. The maximal photocatalytic activity is obtained for the TiO2/Ti photo-anode deposited at a cell voltage of 2.6 V for 20 min and annealed at 700 degrees C in air for 1 hr, which exhibits a photocurrent density of 22.86 mu Amg(-1). The order of degradation modes with respect to decreasing the degradation efficiency of OG is: PEF > EPC > PC (photocatalytic) > EC (electrocatalytic) oxidation. (C) 2014 The Electrochemical Society. All rights reserved.
Single-emission-layer white organic light-emitting devices: Chromaticity and colour-rendering consideration
(2014-02-01)
Fan, Chia-Chan
;
Huang, Ming-Hong
;
Lin, Wei-Chieh
;
Lin, Hao-Wu
;
Chi, Yun
The chromaticity and colour-rendering capability of solution-processed single emission layer (EML) white organic light-emitting diodes (W-OLEDs) can be precisely tuned by manipulating the dopant compositions in the EMLs. In this work, we numerically modelled binary, ternary, and quaternary doping single EML W-OLEDs. The correlated colour temperature (CCT), colour-rendering index (CRI), and spectral designs were correlated. The simulation predicted that the quaternary doping system possesses the best chromaticity performance. The corresponding binary, ternary and quaternary doping single EML W-OLEDs were fabricated and characterised to verify the calculation. The solution-processed quaternary doping W-OLEDs were designed with CRI values up to 85, deviations from the Planckian locus (D-u'v') as low as +0.0009, an EQE of 13.7%, a power efficacy of 14.7 lm/W and current efficiency of up to 24.9 cd/A at 1000 cd/m(2). (C) 2013 Elsevier B.V. All rights reserved.